Heat transfer recording mediums are widely employed in bar code printers, word processors and facsimiles, since they can easily produce clear printed images.
Heat transfer recording mediums employed especially in bar code printers are required to have higher resolution to the bars in printing bar codes with a line printer. However, none of conventional heat transfer recording mediums satisfy this requirement.
Bar codes are read out by moving a pen scanner over printed bar code images which are formed with a heat transfer medium. Accurate readout of information cannot be achieved if bar codes printed on articles are blurred or effaced by rubbing with foreign materials during transportation of the articles. Further, repeated readout may result in abrasion of bar codes with a pen scanner.
Computers are widely utilized for control of automobile parts, and a bar code system is used for data entry. Bar codes formed with conventional heat transfer recording mediums have poor resistance to solvents. Therefore, in assembly or repair shops of automobiles where solvents often adhere to bar codes printed on automobile parts, there can be such a problem that bar codes are blurred or effaced due to solvents adhering thereto.
Under such circumstances, there is a demand for a heat transfer recording medium capable of producing a printed image having excellent resistance to abrasion and a solvent, while it is generally known that the improvement in the resistance of a printed image to abrasion and solvents is liable to deteriorate image quality, which results in lowering resolution to the bars in bar codes.